The present invention relates generally to wireless vehicle tire pressure monitoring, vehicle remote keyless access, and vehicle immobilization and, more particularly, to a system and method employing a combined receiver for shared vehicle tire pressure monitoring, remote keyless entry, and immobilization functions.
It is well known in the automotive industry to provide for remote keyless entry (RKE) to a vehicle through the use of a hand held transmitter, which is commonly referred to as a xe2x80x9cfob.xe2x80x9d Currently available RKE fobs may be separate units, or may be part of an ignition keyhead, preferably along with a vehicle immobilization transponder. Such RKE fobs generally utilize an antenna to transmit radio frequency (RF) signals to a vehicle in order to lock or unlock vehicle doors, open or close a vehicle sliding door, unlock a vehicle trunk, activate internal and/or external vehicle lights, and/or activate a xe2x80x9cpanicxe2x80x9d alarm. Remote access systems using such RKE fobs typically employ on-off keying (OOK) or amplitude shift keying (ASK) modulation schemes for the RF signals.
It is also known in the industry to provide for wireless monitoring of vehicle tire parameters, particularly tire pressure. An exemplary tire monitoring system is described and shown in U.S. Pat. Nos. 5,600,301 and 5,463,374, which also describes a vehicle remote access device. In such tire monitoring systems, RF transmitters mounted inside each tire, typically adjacent the inflation valve stem, transmit information concerning tire pressure to a receiver located on-board the vehicle. The information delivered by the RF signals from the transmitters is subsequently conveyed to a vehicle operator, typically in the form of a display. Like vehicle remote access systems, such tire monitoring systems also typically employ OOK or ASK modulation schemes for the RF signals. When such modulation schemes are used, however, there can be strong adverse effects on reception of the RF signal, because the amplitude of a signal transmitted from a rotating tire can vary significantly during the period of the transmission.
Finally, in order to deter theft, it is also known in the automotive industry to provide systems for vehicle immobilization. U.S. Pat. No. 5,670,933 illustrates an example of such an immobilization system. Such vehicle anti-theft devices typically employ low frequency (LF) transponders in a vehicle ignition keyhead. In such systems, upon insertion of the vehicle ignition key into the vehicle ignition keyhole, an interrogation signal is sent by the vehicle. In response, the keyhead transponder transmits an encrypted code to a control unit, such as a microprocessor, on-board the vehicle. If the code sent by the transponder is valid (i.e., the control unit authenticates the received code), then the control unit generates a signal operative to permit the vehicle to be activated. However, if the code is not received by the control unit, or if the code is not valid (i.e., the control unit cannot authenticate the received code), then the control unit generates a signal operative to immobilize the vehicle, for example by cutting off the fuel supply to the vehicle engine.
It would be desirable to provide a system and method for shared vehicle remote access, tire monitoring and vehicle immobilization. Such a combined system and method would provide an improved and simplified design for such functionality, thereby optimizing performance and providing a cost advantage. In particular, such a system and method would preferably employ a combined RKE, tire monitoring and vehicle immobilization receiver and a single microprocessor controller. Such a system and method would also preferably use an OOK or ASK modulation scheme for RKE, while employing a more advantageous frequency shift keying (FSK) modulation scheme for tire monitoring, thereby overcoming the problems of the prior art tire monitoring systems described above. Still further, such a system and method would also preferably provide an advantageous RF link for use in vehicle immobilization.
Accordingly, it is an object of the present invention to provide a system and method for shared vehicle remote access, tire monitoring and vehicle immobilization functions in order to improve performance and reduce expense. In that regard, it is a further object of the present invention to preferably employ a combined remote keyless entry (RKE), tire monitoring and vehicle immobilization receiver and a single microprocessor controller. It is also an object of the present invention to preferably use an on-off keying (OOK) or amplitude shift keying (ASK) modulation scheme for RKE, while preferably employing a more advantageous frequency shift keying (FSK) modulation scheme for tire monitoring, as well as to preferably provide an advantageous radio frequency (RF) link for use in vehicle immobilization.
According to the preferred embodiment of the present invention, a combined vehicle remote access, tire monitoring and vehicle immobilization system is provided for use with an automotive vehicle. The system comprises a tire monitor for mounting in a vehicle tire for monitoring at least one tire parameter, the monitor including a transmitter for transmitting a radio frequency tire data signal representing information concerning the at least one tire parameter, a handheld remote vehicle access transmitter for transmitting a radio frequency vehicle access signal for use in performing at least one vehicle access function, and a vehicle activation transponder for receiving an interrogation signal and transmitting a vehicle activation signal for use in a vehicle immobilization function. The system further comprises a control module for mounting on-board the vehicle, the control module including a receiver for receiving the tire data, vehicle access, and vehicle activation signals, and a controller for processing the tire data, vehicle access, and vehicle activation signals and generating a display signal operative to display to a vehicle operator the information represented by the tire data signal, a vehicle access control signal operative to perform the at least one vehicle access function, and a vehicle immobilization control signal operative to immobilize the vehicle if the controller fails to authenticate the vehicle activation signal.
According to another aspect of the present invention, a method for combined vehicle remote access, tire monitoring and vehicle immobilization is also provided for use with an automotive vehicle. The method comprises providing a tire monitor for mounting in a vehicle tire for monitoring at least one tire parameter, the monitor including a transmitter for transmitting a radio frequency tire data signal representing information concerning the at least one tire parameter, providing a handheld remote vehicle access transmitter for transmitting a radio frequency vehicle access signal for use in performing at least one vehicle access function, and providing a vehicle activation transponder for receiving an interrogation signal and transmitting a vehicle activation signal for use in a vehicle immobilization function. The method further comprises providing a control module for mounting on-board the vehicle, the control module including a receiver for receiving the tire data, vehicle access, and vehicle activation signals, and a controller for processing the tire data, vehicle access, and vehicle activation signals and generating a display signal operative to display to a vehicle operator the information represented by the tire data signal, a vehicle access control signal operative to perform the at least one vehicle access function, and a vehicle immobilization control signal operative to immobilize the vehicle if the controller fails to authenticate the vehicle activation signal.
These and other objects, features and advantages of the present invention will be readily apparent upon consideration of the following detailed description of the invention in conjunction with the accompanying drawings.